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Chemical contamination on the International Space Station

estación espacial internacional, contaminantes químicos, calidad de aire

A new study shows that levels of potentially harmful chemical compounds in dust collected by air filtration systems on the International Space Station (ISS) are higher than in the dust on the floors of many American homes.

This information is important for assessing and improving air quality on the ISS, as well as understanding potential health risks for astronauts living and working there.

In groundbreaking research, scientists examined a sample of dust from air filters on the International Space Station (ISS) and found that levels of organic pollutants were higher than average in homes in both the United States and Europe. This raises questions about air quality inside the ISS and underscores the importance of taking steps to ensure a safe environment for astronauts.

By publishing its results today in Letters on Environmental Science and TechnologyAccording to researchers from the University of Birmingham (UK) and NASA’s Glenn Research Center (USA), their findings could serve as a guide for the design and construction of future spacecraft.

Pollutants found on the International Space Station

Pollutants found in “space dust” included polybrominated diphenyl ethers (PBDE), hexabromocyclododecane (HBCDD), “new” brominated flame retardants (BFR), organophosphorus esters (OPE), polycyclic aromatic hydrocarbons (PAH), perfluoroalkyls (PFAS), and polychlorinated biphenyls ( PCBs).

Brominated flame retardants (BFRs) and polybrominated diphenyl ethers (OPEs) are widely used in many countries to meet fire safety regulations in consumer and commercial applications. These chemicals are used in electrical and electronic equipment, building insulation, upholstery fabrics and foams. Its function is to reduce the risk of fire spreading and to improve safety in this context.

PAHs are found in hydrocarbon fuels and are emitted during combustion processes. PCBs are used in building and window sealants and electrical equipment as dielectric fluids, while PFAS are used in fabric and clothing anti-stain applications. However, their potential impact on human health has led to some being banned or restricted in their use.

pollutant classification

According to the United Nations Environment Program (UNEP) Stockholm Convention, PCBs, some PFAS, HBCDD and the commercial formulations of the PBDEs penta-octa and deca-BDE are classified as persistent organic pollutants (POPs). These chemical compounds pose a significant risk to the environment due to their persistence and potential toxicity.

It is important to take appropriate measures to reduce its consumption and minimize its impact on human health and ecosystems. Notably, some PAHs (polycyclic aromatic hydrocarbons) have been classified as carcinogenic to humans.

On the other hand, the European Chemicals Agency is considering restricting some OPEs (organophosphates) due to their possible negative effects on human health.

Study author’s comments

Co-author Professor Stuart Harrad from the University of Birmingham commented: “Our findings have implications for future space stations and habitats, where it might be possible to eliminate many sources of pollution through careful material selection in the early stages of design and construction.”

“While the levels of organic pollutants detected in the ISS dust often exceeded the mean levels found in homes and other indoor environments in the United States and western Europe, the levels of these compounds were generally within the range found on Earth .”

The researchers note that concentrations of PBDEs in the dust sample that fall within the range of concentrations detected in US household dust may be due to the ISS’s use of inorganic RFs such as ammonium dihydrogen phosphate to manufacture fabrics and harnesses. fire retardant They believe the use of commercially available “standard” items that astronauts bring on board for personal use, such as cameras, MP3 players, tablets, medical equipment and clothing, are potential sources of many of the chemicals discovered.

The air inside the International Space Station

The air inside the ISS is constantly being circulated at 8-10 changes per hour. While removal of CO2 and trace gases is occurring, the level of removal of chemicals such as BFRs is unknown. High levels of ionizing radiation can accelerate the aging of materials, including the decomposition of plastic products into airborne micro- and nanoplastics in the microgravity environment. This may result in the concentrations and relative abundances of PBDEs, HBCDDs, NBFRs, OPEs, PAHs, PFASs, and PCBs in the ISS dust being significantly different from dust in the Earth’s indoor microenvironments.

Scientists have measured the concentrations of a range of target chemicals in dust collected from the ISS. In a microgravity environment, particles float according to the flow patterns of the ventilation system and eventually settle on surfaces and air intakes.

The screens covering the ISS’s HEPA filters collect this debris and must be vacuumed weekly to maintain efficient filtration. The material in the ISS vacuum bags consists of previously airborne particles, clothing fluff, hair and other debris commonly identified as spacecraft cabin dust. Some vacuum bags have been returned to Earth for study of this unique dust. A small sample was sent to the University of Birmingham for analysis as part of the study.

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